Let's try this last time...

Url??

The sandy beach image is the image that I've chosen for the background on my blog,

however, instead of stating allowable pixel widths and file sizes,
it has a space for copy/pasting the " URL" of the image.

There is a basic template with a select choice of "colors" to chose from,
but then there is also a feature to "switch templates" and " customize"...
with which others on the forum have been successfull.

I did get the image from a free website, yet the image needed editing as it was too large. Will you explain step-by-step the "how to's" of transfering my image from my PC back in that URL address...or is this possible?

Almost certainly, you won't be able to put the edited image back to the same website where you found it. I'd guess that the site you used makes images available for download, but allowing upload is a whole different thing.

If the only option for your blog image is to specify an URL, then you need some web space of your own to upload the image to. You need to either find a free website service or pay for one, then upload the edited image and use the new URL. Looks like you've got a bit of work yet to do

In the meantime (for testing purposes) you can use the image URL you created by uploading the image here. If you right-click the beach image in your message and select "Properties", you will see the URL (location) is:

Copy and paste this URL into the appropriate field in your blog. If it works, you're getting there. Then you'll need to find your own place to upload the image to, since the mediacollege one will become unusable in time.